Have you thought of getting the Butler to phone the stealers and asking them??
Thats a good idea, better than thinking a tosser like you could help.
you are clearly new to the forum, this forum runs of a little ****take, don't take it personally its not meant that way, i'm sure one of the other RR owners will tell you what pressure you should have or you could as mr redhand said phone the dealer and ask what the 'recommended' tyre pressure should be.
i run on 19s, i got 32 and 36 in back..